Studies are being conducted on the effect of adriamycin, 4'-epi-adriamycin 4-demethoxy adriamycin, and 5-iminodaunorubicin in transcription in mouse leukemia cell lines (P388 and L1210). More specifically the investigations include the drugs effects on the physical-chemical properties of DNA and chromatin and the investigation of their effect on transcription utilizing DNA, chromatin, nuclei, and polysomes. The most recent work involves a comparison of the effects of each of these drugs on the synthesis of the various types of nuclear and polysomal RNA. Measurements have been made of each of the drugs effects on total RNA synthesis both in the presence and absence of actinomycin D. In addition each of the various types of RNA, ribosomal, poly (A) hnRNA, non-poly (A) hnRNA, poly (A) mRNA and non-poly (A) mRNA have been isolated from control cells and from cells which have been treated with each of the drugs. The purpose of the investigation is to determine if there is a correlation between antitumor effects and inhibition of the synthesis of certain types of RNA.